The rotary bored piling method refers to the installation of piles using drilling techniques.
Bored piles are drilled using buckets and/or augers inside a temporary casing driven in place by means of vibratory hammers or through twisting in place using the drilling rig itself. The temporary casing maintains the upper soil layers stable especially in water bearing stratum. Depending on the designed toe level of the pile, drilling underneath the casing may take place in stable soils such as soft rock or cohesive soils.
In unstable soil strata beneath the toe level of the top casing, the use of bentonite fluid or polymer assists in stabilising the bore especially in large diameter deeper piles. It also allows the perfect insertion of heavily reinforcing steel cages. NSCC possesses the most modern fleet of large diameter heavy-duty rotary piling rigs capable of drilling to depth exceeding 75 metres.